(1) Field of the Invention
This invention relates to an automatic locking retractor suitable for use in a vehicle seat belt system and producing little unpleasant noise when winding the webbing into the retractor.
(2) Description of the Prior Art
In a vehicle seat belt equipped with a so-called automatic locking retractor, the webbing wound up on the retractor is pulled out and worn by the occupant. The webbing is then allowed to be rewound on the retractor over any extra length thereof. When the occupant tries to pull out the webbing again, the webbing is restrained from any further release. A variety of different types of such automatic locking retractors has been proposed and actually used to date (see, for example, U.S. Pat. No. 3,412,952 issued Nov. 26, 1968 to Wohlert et al, U.S. Pat. No. 3,667,698 issued June 6, 1972 to Fisher, etc.).
Many of such prior art automatic locking retractors are of such a type that they are each constructed of a pair of cog wheels integral with a take-up spindle, on which a webbing is releasably wound up, and a lock lever normally urged or biased in a direction capable of engaging with the cog wheels and controlled by a cam plate.
An automatic locking retractor of the above type is however accompanied by an inconvenience that an unpleasant noise is produced due to contact between the cog wheels and lock lever particularly when winding the webbing into the retractor, because the lock lever is normally urged in the direction capable of engaging with the cog wheels. Since these cog wheels and lock lever have to be made of a metal as forces are exerted thereto, it is considerably difficult to lower the contacting noise between these metal parts.
It may be contemplated to apply a resin coating onto the surface of the lock lever as a method for solving the above problem. It is however necessary to make the resin coating significantly thick. This however leads to a danger that a thick resin coating may induce a slippage of the lock lever from the cog wheels and vice versa when the resin-coated lock lever is brought into engagement with the cog wheels.
As an alternative method, it may also be contemplated to hold the lock lever in a non-engagement position with the cog wheels by means of a cam plate when winding the webbing. This method is however accompanied by such a potential danger that the lock lever may be kept in the non-engagement position or its engagement with the cog wheels may be delayed, thereby failing to achieve sure restraint of any further release of the webbing.